Natural Organic Matter, Orthophosphate, pH, and Growth Phase Can Limit Copper Antimicrobial Efficacy for Legionella in Drinking Water
Natural Organic Matter, Orthophosphate, pH, and Growth Phase Can Limit Copper Antimicrobial Efficacy for Legionella in Drinking Water
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DOI：
10.1021/acs.est.0c06804
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发表时间：
2021-01-11
影响因子：
11.4
通讯作者：
Rhoads, William J.
中科院分区：
文献类型：
--
作者：
Song, Yang;Pruden, Amy;Rhoads, William J.
铜（Cu）是用于房屋管道的有前景的抗菌剂，其中离子可以通过铜银电离直接给药或通过Cu管道的腐蚀自然释放，但Cu有时抑制军团菌生长，有时刺激军团菌生长。我们的总体假设是，水化学和生长阶段控制铜对军团菌的净效应。pH值，磷酸盐浓度，和天然有机物（NOM）的综合影响进行了全面检查在一系列条件下相关的饮用水在实验室规模的纯培养实验，照亮的Cu形态和沉淀的影响。发现在pH > 7.0或存在形成配体的磷酸盐或NOM的情况下，铜离子（Cu 2+）急剧减少。pneumophila对Cu毒性的敏感性是早期稳定期培养物的2.5倍。虽然Cu 2+离子是Cu的最有效的杀生物形式，但其他无机配体也具有一定的杀生物作用。对1990年和2018年33个大型饮用水公用事业现场数据的比较表明，近几十年来，Cu2+水平的下降可能比总铜或可溶性铜（2x）的下降幅度更大（> 10倍）。总体研究结果有助于提高铜作为主动给药或被动释放的抗菌剂对乳酸杆菌的功效。嗜肺菌
Copper (Cu) is a promising antimicrobial for premise plumbing, where ions can be dosed directly via copper silver ionization or released naturally via corrosion of Cu pipes, but Cu sometimes inhibits and other times stimulates Legionella growth. Our overarching hypothesis was that water chemistry and growth phase control the net effect of Cu on Legionella. The combined effects of pH, phosphate concentration, and natural organic matter (NOM) were comprehensively examined over a range of conditions relevant to drinking water in bench-scale pure culture experiments, illuminating the effects of Cu speciation and precipitation. It was found that cupric ions (Cu2+) were drastically reduced at pH > 7.0 or in the presence of ligand-forming phosphates or NOM. Further, exponential phase L. pneumophila were 2.5x more susceptible to Cu toxicity relative to early stationary phase cultures. While Cu2+ ion was the most effective biocidal form of Cu, other inorganic ligands also had some biocidal impacts. A comparison of 33 large drinking water utilities' field-data from 1990 and 2018 showed that Cu2+ levels likely decreased more dramatically (>10x) than did the total or soluble Cu (2x) over recent decades. The overall findings aid in improving the efficacy of Cu as an actively dosed or passively released antimicrobial against L. pneumophila.